An analysis of the morphology, amplitude and latency of visual evoked potentials to photic flashes and reversing checkerboard pattern being conducted. Normative data so far have been collected from some 70 individuals, predominantly of 20-39 years. Visual evoked responses also have been examined in some 60 patients with various neurological disorders. Prolonged latencies of the major positive peak have been noted in patients with multiple sclerosis and other neurological disorders.